I think you might be right! Edna's tail feathers are fine today but she is clearly being pecked at, and probably on the roost. She slept in that tighter corner last night. Red also looks normal today, and Teddy, a different hen, is showing signs of being pecked at. I noticed tensions are a bit high right now, a couple girls got into a squabble yesterday. I wonder why... ah well, seems like a non-issue.
Since this is a recurring thing, I guess it means they're just getting at each other sometimes.